<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		p:first-letter{
			color:red;
			font-size:30px;
		}
		p:first-line{
			background:pink;
		}
		p:before{
			content:"嘿嘿";
		}
		p:after{
			content:"哈哈";
		}
	</style>
</head>
<body>
	<p>
		hello world <br>
		welcome to css
	</p>
</body>
</html>